Hierarchically-Interlocked, Three-Axis soft Iontronic Sensor for Omnidirectional Shear and Normal Forces

Abstract

Artificial tactile sensing capable of measuring shear and normal forces is crucial for the diverse human-machine interactions and dexterous robotic manipulations. However, existing soft multi-axis force sensors usually suffer from limited detectable directions and complex coupling mechanisms, limiting their applications in realistic wearable and robotic systems. Here, a hierarchically-interlocked, three-axis soft iontronic sensor is presented with an asymmetrical electrode pattern that leverages the mortise-and-tenon structure and ultracapacitive principle to detect omnidirectional shear and normal forces. The designed sensor facilitates the decoupling process and achieves enhanced sensing performances including high accuracy, fast response ability, and mechanical robustness. Prototypical integration and application of the sensor are demonstrated to perform wearable telecontrol of virtual platforms and assist robot gripper through closed-loop force feedback. A sensing array is further developed to construct a touch panel and identify handwriting based on the continuously measured directions of applied forces. This work may offer a potentially promising solution for the next-generation intelligent electronic skins requiring multimodal tactile sensing information.